"Random sample controls" have been a distinctive feature of
the Virginia Division of Forensic Science's protocol of DNA testing.
According to the lab's protocol:

A random control will be run with each extraction to
serve as an extraction, amplification, and a typing gel migration control.
The random control is a previously analyzed convicted offender sample for
which the identity of the sample is known to the Forensic Biology Program
Manager and Laboratory Directors. This sample serves as an internal
laboratory control since the DNA profile is not known to the
examiner/analyst and must be verified by the Forensic Biology Program
Manager or the Laboratory Director prior to the sizing data being
considered acceptable. If a sample must be re-extracted a new
sample must be extracted along with the sample. (Section 1.1.12)

After developing a profile for the random sample control, the analyst
searched the profile against the CODIS database to see if a
"hit" could be obtained to the right person. The
"hit" confirmed the accuracy of the lab's procedures by showing
that DNA from someone already in the database could reliably be typed and
matched back to that same person.

At least that was the theory. Laboratory notes from the case of Virginia
v. Leon Winston (see links below to copies of these notes) suggest
that in practice the lab took a cavalier approach to the random sample
controls. Getting an incomplete profile, or even the wrong profile,
apparently was not seen as a problem.

If Your Control Fails, Substitute Another

On page 44 of the lab notes, the profile of one random control
(STR2001-0057), as typed by analyst Nicole Harold, is shown in Lane
5. No results were observed for TPOX and results for PentaD and
CSF1PO are crossed out and marked "Inc." Page 50 of the
lab notes show that a second reader of the gel (initials "PJT")
also marked the results for PentaD and CSF1PO
"INC."

Was this incomplete profile considered a problem? Apparently
not. When Harold searched the profile against CODIS, she entered a
genotype for CSF1PO even though both readers had indicated this locus was
inconclusive. A handwritten note on the State Match Results Report
(lab notes page 51) says "CSF1PO results from another
gel."

The stated purpose of the random sample is to serve as a control for
"extraction, amplification and gel migration." To
substitute data from another gel obviously defeats that purpose. An
analyst who says, in effect, "my control failed in this experiment,
so I'll use data obtained on the control sample in another experiment"
has failed to grasp an essential element of the scientific method.
That logic would fail to pass muster at a junior high school science fair.

If you are wondering what Harold would have done if she had obtained
incorrect results from a random sample, rather than merely incomplete
results, read on.

That situation arose on a second gel run in the Winston case. On
page 102 of the lab notes, the profile of a second random control
(STR2001-0046), as typed by Nicole Harold, is shown in lane 5.
The second reader's typing of the same sample is shown on page 110 of the
lab notes, also in Lane 5. Both Harold and the second reader
reported a complete profile. But the State Match Report (lab notes
page 111) shows that Harold searched a different profile against
CODIS. For locus PentaD, the random sample was typed as a 9,12, but
the "type" Harold searched against CODIS was a 12. For locus
CSF1PO, the random sample was typed as 12,12, but the
genotype compared to CODIS was 11,12. A handwritten
annotation on the lab notes explains: "CSF1PO and PentaD results from
other gel." So Harold must somehow have known that the random
sample had been typed incorrectly on the gel in the Winston case.
She responded to the failure of this scientific control by again
substituting data from another gel (apparently from another
case).

Needless to say, by any conventional scientific standards the failure
of a positive control requires re-running the assay or experiment in which
the control failed. In other words, the DNA testing in the Winston
case should have been treated as invalid and re-run.

Did the Independent Reviewers Notice This Problem?

The Winston case was one of 150 cases recently reviewed by an
independent scientific panel appointed by the Governor of Virginia in the
wake of the scandal over the Earl Washington case (see ASCLD-Lab
Review). The panel, chaired by Arthur Eisenberg, issued
a report on September 12, 2005. Although the independent panel's
report discussed the Winston case, mentioning a problem with the
statistical computations, it said nothing about the problems with the
random sample controls. This raises an interesting and important
question. Did the panel fail to notice these problems (perhaps
because they did not receive complete documentation on the case)?
Did the panel notice the annotations about substituting results from other
gels and conclude that this was not a problem? Or did the panel fail
to notice the problem, perhaps due to a cursory and inadequate
review? Inquiring minds want to know.

If Your Control Fails, Discontinue It?

As of January 11, 2005 (more than two years after the Winston case was
processed), the Virginia Division of Forensic Sciences decided to
stop running random sample controls. The memo
announcing that these controls should be discontinued "in order to
improve turnaround time for the analysis of casework" was signed by
Jaffrey Ban, Forensic Biology Section Chief. Ban was relieved of his
duties as Technical Leader of the Virginia Division of Forensic Sciences
DNA laboratories in May 2005, after the ASCLD-LAB Audit Report
(dated April
9, 2005) faulted him for errors and misinterpretation of DNA testing in
the Earl Washington case.

Canaries and Controls

Scientific controls are like the proverbial canary in a coal
mine. A failed control, like a dead canary, indicates an unheathy
state of affairs. And discontinuing the use of controls, like
banning canaries from the mine, is a way to hide rather than solve the
underlying problem.

Report of
Independent Review Panel (finding a problem with the statistical
calculations in the Winston case as earlier noted by Thompson but, apparently, no problem with the
random sample controls)

Update of Lovitt Case (July 9, 2005)

William C. Thompson

When asked about the state's decision to deny Lovitt's lawyers access
to electronic STR data that could clarify whether he is really guilty, a
spokesperson for the Governor told
the Richmond Times-Dispatch that the conclusions of an outside review
team were sufficient to address the issue. This response
confuses two issues.

One issue is whether the Virginia DFS laboratory properly conducted and
interpreted the DNA tests in Lovitt's case. The outside reviewers
found no deviations from the lab's standard protocol and therefore found
no problem with the lab's work. I agree with that conclusion.

The second issue is whether Lovitt received a fair trial, and
specifically whether the DNA evidence was presented to Lovitt's jury in a
misleading way. Dr. Arthur Eisenberg of the review panel confirmed
today that the outside review panel has not reviewed transcripts of the
trial. As explained above, I believe the trial was not fair because
the jury did not receive a balanced account of the DNA evidence.

Because the outside review panel addressed the first issue, and not the
second, the findings of the review panel do not address concerns about the
fairness of Lovitt's trial. Hence, the Governor's staff is mistaken if
they believe the findings of the review panel respond to the concerns
raised here and elsewhere about the fairness of Lovitt's trial.

In light of the continuing concerns about the fairness of Lovitt's
trial, and the possibility that he might actually be innocent, it seems
unconscionable for the state to continue denying Lovitt's lawyers access
to electronic STR data that could clarify whether he is really guilty.

July 7, 2005

Although Robin Lovitt is scheduled for execution on July 11, 2005,
substantial questions still exist about his guilt or innocence--questions
that might be resolved by further analysis of existing scientific data
that the state has refused to disclose to Lovitt's lawyers.

The facts of the case are nicely summarized in a recent
editorial by Margaret Edds in the Virginian-Pilot. The editorial
laments the fact that two crucial items of biological evidence (blood
stained scissors that were used to fatally stab the victim and the
defendant's bloody clothing) are not available for additional DNA testing
because they were illegally thrown away by a state official. An
initial round of DNA testing in 1999 by the Virginia Division of Forensic
Science produced "inconclusive" results, but newer tests could
be more definitive. Although the editorial says these items were
discarded by error, it
now appears that the destruction of evidence was intentional misconduct.

I recently prepared a declaration
that makes three important points about the Lovitt case.

First, the DNA evidence against Lovitt was presented in a misleading
way. A highly problematic test result on the murder weapon
(scissors) was presented to the jury in a manner that suggested it
provided significant support for the proposition that Lovitt handled the
murder weapon. I believe most experts would view this result, which
was used against Lovitt, as more exculpatory than
incriminating.

Second, the DNA test results suggest that the blood stains on Lovitt's
jacket, which the prosecutor attributed to the victim, could not have been
from the victim and were actually from Lovitt himself.
Although the
test results on the jacket were deemed “inconclusive” by the Division
of Forensic Sciences, these results appear to be far more complete
and revealing than the test results that were used to link Lovitt to the
murder weapon.
I believe the government applied a double standard in this case.The extremely weak and problematic results that linked Lovitt to
the murder weapon were presented to the jury and used as a basis for
arguing that he was the killer.But the jury was never told about the relatively stronger and more
convincing results that supported Lovitt’s innocence by showing that the
blood on his jacket did not come from the victim, as the prosecutor had
argued, but came from Lovitt himself.

Third, and most important, despite the loss of the original biological
sample, it may still be possible to draw more definitive conclusions about
the DNA on the scissors and the jacket through re-analysis of electronic
data collected by the state lab in its initial round of testing. The
existing electronic data could be re-analyzed using new analytic methods
in order to clarify the test results. Unfortunately, the state has
repeatedly refused the requests of Lovitt's lawyers for copies of these
electronic files. The state appears intent on proceeding with
Lovitt's execution without giving Lovitt's lawyers an opportunity to
examine evidence that conceivably could support his claim of
innocence. This hardly seems fair.

I invite others to review the materials that I reviewed in order to see
whether they agree with my assessment of the case. I have made
available here everything that I reviewed, including:

Lab reports and lab
notes--These are obviously incomplete. There are no notes,
for example, on DNA extraction or amplification. But Lovitt's
lawyers have told me these notes represent the sum total of all
materials about the DNA testing that the state was willing to
disclose. Of particular note are the StaRCall printouts, showing
the alleles detected by the state lab's software.

As mentioned, I am very interested in hearing views of others on this
case, particularly DNA experts. Click
here to e-mail your comments. I'll post the most interesting
comments here (whether they agree with me or not).

Other Errors in DNA Testing

March 20, 2003

News of the exoneration of Josiah Sutton has raised questions about
other cases in which DNA evidence has produced false incriminations.
In a recent article in the Journal of Forensic Sciences (January 2003),
William Thompson, Franco Taroni, and Colin Aitken discuss several cases
where such errors occurred. We provide documentation on some of
those errors here.

March 11, 2003

The Houston Police Department acknowledged yesterday that new DNA tests
appear to exonerate a man serving a 25 year sentence for rape.
Josiah Sutton was convicted in 1999 based largely on DNA tests performed
by the Houston Police Crime Laboratory. Yesterday's announcement
confirms the position of UC Irvine Professor William Thompson, who told
several news organizations in January that he though Sutton was probably
innocent (see story below). It also vindicates forensic scientist
Elizabeth Johnson, a long-time critic of the Houston Police Department
Lab, who has complained about incompetence and bias in the lab's work.

March 7, 2003

Last Fall, several DNA experts went public with accusations that the
DNA/Serology Unit of the Houston Police Department Crime Laboratory was
doing grossly incompetent work and presenting findings in a misleading
manner designed to unfairly help prosecutors obtain convictions.

The story was broken by Houston television station KHOU. See news
accounts and streaming video on these accusations at the KHOU
Website.

In response to these accusations, the Houston Police Department asked the
Texas Department of Public Safety (DPS) to audit the DNA/Serology
Unit. The audit report, released in January, confirmed serious
inadequacies in the laboratory's procedures, including routine failure to
run essential scientific controls, failure to take adequate measures to
prevent contamination of samples, failure to adequately document work
performed and results obtained, and routine failure to follow correct
procedures for computing statistical frequencies. Click
here to see a copy of the audit report.

In January, UC Irvine Professor William Thompson told KHOU, the Houston
Chronicle, and the New York Times, that he thought the HPD Crime
Laboratory had falsely incriminated an innocent man in a 1999 rape
case. Key documents related to the case of Texas v. Josiah Sutton
can be located through the following links:

Link to article describing Gerdes' pivotal study of the LAPD DNA lab. Raises important issues
about susceptibility of PCR-based tests to contamination and about the adequacy of the standard
controls designed to detect contamination.